1. Field
The present disclosure relates to a negative electrode including metal/metalloid nanotubes, a lithium battery including the negative electrode, and a method of manufacturing the negative electrode.
2. Description of the Related Art
Carbonaceous materials such as graphite are representative examples of negative electrode active materials for lithium batteries. Graphite has excellent electrical capacity retention characteristics and excellent voltage characteristics. In addition, since graphite does not vary in volume when lithium is intercalated or deintercalated, graphite can increase the stability of batteries. Graphite has a theoretical electrical capacity of about 372 mAh/g and a high irreversible capacity.
In addition, metals capable of forming alloys with lithium may be used as a negative electrode active material for lithium batteries. Examples of metals capable of forming alloys with lithium include silicon (Si), tin (Sn), aluminum (Al), and the like. These metals have a very high electrical capacity. For example, these metals may have an electrical capacity that is 10 times higher than that of graphite. However, such metals undergo volume expansion or shrinkage during charging/discharging, thereby electrically isolating the active material within the electrode. In addition, the decomposition reaction of electrolytes becomes severe, due to an increase in the specific surface area of the active material.
In order to suppress the volume expansion and decomposition reaction of electrolytes, metals capable of forming alloys with lithium may be formed with nano-sized structures. For example, Si-nanowires may be used. However, Si-nanowires have a high volume expansion rate and may be cracked during charging/discharging.
Therefore, there is a demand for a negative electrode for lithium batteries that includes a high-capacity negative electrode active material having the ability to absorb stress due to volume expansion and thereby, have a high durability.